In Maxwell's electromagnetic theory, for example, the fields E and [B] are `physical' (beables, we will say) but the potentials A and \(\phi \)  are `non-physical'. Because of gauge invariance the same physical situation can be described by very different potentials. It does not matter that in Coulomb gauge the scalar potential propagates with infinite velocity [see Eq. (REF )]. It is not really supposed to be there. It is just a mathematical convenience [1]}."
